/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.coders;



import com.bff.gaia.unified.sdk.values.TypeDescriptor;

import com.bff.gaia.unified.sdk.values.TypeParameter;



import java.util.ArrayList;

import java.util.List;



/**

 * A {@link Coder} for {@link List}, using the format of {@link IterableLikeCoder}.

 *

 * @param <T> the type of the elements of the Lists being transcoded

 */

public class ListCoder<T> extends IterableLikeCoder<T, List<T>> {



  public static <T> ListCoder<T> of(Coder<T> elemCoder) {

    return new ListCoder<>(elemCoder);

  }



  /////////////////////////////////////////////////////////////////////////////

  // Internal operations below here.



  @Override

  protected final List<T> decodeToIterable(List<T> decodedElements) {

    return decodedElements;

  }



  protected ListCoder(Coder<T> elemCoder) {

    super(elemCoder, "List");

  }



  @Override

  public boolean consistentWithEquals() {

    return getElemCoder().consistentWithEquals();

  }



  @Override

  public Object structuralValue(List<T> values) {

    if (consistentWithEquals()) {

      return values;

    } else {

      List<Object> ret = new ArrayList<>(values.size());

      for (T value : values) {

        ret.add(getElemCoder().structuralValue(value));

      }

      return ret;

    }

  }



  /**

   * List sizes are always known, so ListIterable may be deterministic while the general

   * IterableLikeCoder is not.

   */

  @Override

  public void verifyDeterministic() throws NonDeterministicException {

    verifyDeterministic(this, "ListCoder.elemCoder must be deterministic", getElemCoder());

  }



  @Override

  public TypeDescriptor<List<T>> getEncodedTypeDescriptor() {

    return new TypeDescriptor<List<T>>(getClass()) {}.where(

        new TypeParameter<T>() {}, getElemCoder().getEncodedTypeDescriptor());

  }

}